This invention pertains to a valve assembly for controlling particulate solids feed, and particularly relates to such a control valve assembly utilizing a purged poppet valve head and seat and guide bushing configuration for feeding particulate solids upwardly into a vessel, such as coal to a gasifier.
The feeding of particulate solids into a vessel such as coal into a gasifier is generally known. For example, U.S. Pat No. 2,088,679 to Yamazaki et al. shows feeding of solid fuel such as coal to a gasifier by a horizontal screw conveyor. U.S. Pat. No. 2,667,409 to Hubmann shows a gas producer having a poppet type valve located at its lower outlet end for ash removal. Also the need to purge valve seat mating surfaces for valves handling particulate solids is generally known. For example, U.S. Pat. No. 3,703,908 to Tellier shows a poppet valve and seat arrangement in which entrapped gas is squirted through the mating seat to purge it. U.S. Pat. No. 4,188,174 to Perkins shows a valve handling abrasive slurries in which the valve seat is purged by a washing fluid supplied through an annular outlet. Also, U.S. Pat. No. 3,470,899 to Cusi shows a valve having a purged guide bushing.
Although considerable efforts have been made in the past to develop control valve systems suitable for reliably feeding of particulate solids to vessels, none of the known prior art valve arrangements have been found to be entirely satisfactory for handling the upflow of particulate solids into vessels such as coal into a gasifier.